Note: In Europe, Alces alces is referred to by the common name elk, whereas in North America the common name used is moose. A. alces is divided into two main types, western and eastern, which have a hybrid zone in the Yenisei River valley and Altai Mountains (central Siberia). Lister 2005.

Axis axis [Axis Deer | Chital | Indian Spotted Deer]
× Axis porcinus (↔ usu. ♂) [Hog Deer] CHR. HPF. CON: India. Backcrosses to A. axis have been reported. The cross has occurred in both directions. McMaster (1871, p. 113) describes a young hybrid female produced in an Indian zoo as being of a darker color than her axis deer father and with fainter spots. He also said she “carries her head low like her porcine mother and thus runs with the back apparently much arched. The ears struck me as being larger than those of a spotted fawn of about the same age or size.” Gray says one hybrid resembled A. porcinus "in head, face and horns." Dathe 1966†; Gray 1971 (p. 150); International Zoo Yearbook 1966 (p. 400), 1967 (p. 318), 1968 (p. 307), 1969 (p. 236); 1977 (p. 324); Rörig 1903.
× Cervus duvaucelii [Swamp Deer | Barasingha] CHR. CON: Pakistan, India? International Zoo Yearbook 1970 (p. 271). See also: Axis axis × Cervus nippon.
× Cervus elaphus (♀) [Red Deer | Elk | Wapiti] Some authors (e.g., Gray 1972, p. 150) list this cross on the basis of reports that refer to “Spotted Deer” a common name used for both A. axis and Cervus nippon. The hybrids in question in such reports are usually Cervus elaphus × C. nippon (q.v.). However, Röse (1869, pp. 199-200) does report this cross and gives details. The parents were raised together and produced four hybrids, three stillborn, from four pregnancies. The fourth pregnancy was unusual in that the red deer mother was impregnated both by the Axis mate as before, but also by a C. elaphus stag. After an eight-month gestation, the mother gave birth to a dead hybrid calf, but one month later, a healthy, pure red deer calf was born. The single, viable hybrid calf reached adulthood.
× Cervus nippon [Sika Deer] A hybrid resulted when a chital and a sika crossed on the estate of the President of India. This hybrid doe then crossed to a buck swamp deer at the New Delhi Zoo. The resulting hybrid doe resembled a swamp deer. International Zoo Yearbook (1972, p. 336).
× Cervus timorensis (♂) [Rusa] CHR. DRS. The Paris menagerie (Jardin des Plantes) had a hybrid in 1840. Geoffroy Saint-Hilaire 1840.
× Cervus unicolor [Sambar] NHR? Gono Semiadi (pers. comm. to the IUCN, 2006; Intenet Citations: SAMBA, accessed June 3, 2012) says hybridization is probably occurring in Sumatra between the sambar and the introduced axis deer.
× Dama dama [Fallow Deer] The Bartlett Society website (tinyurl.com/hey3grd; accessed July 12, 2012) lists this cross, citing Bennett (1835, p. 256), who says, “it is even stated on the authority of Peter Collinson that a mixed progeny has been obtained between them [i.e., axis deer] and the Fallow-Deer.” However, Bennett, writing in the first half of the 19th century, uses the name “Fallow-Deer” (and, in several places, “Virginia Fallow-Deer”) which has to be interpreted as Odocoileus virginianus, not Dama dama.
×Hemitragus jemlahicus (♂) [Himalayan Tahr | Jharal] CHR. See the separate article "Himalayan Tahr × Axis Deer hybrids."
+ Muntiacus muntjak [Indian Muntjac] Buffon (1827, p. 174) reported no hybrids of this type, but he does mention that a male Indian muntjac shipped to Europe with a female axis deer was "tormented with desire to cover her, but was too small to succeed" ("Il y avait avec lui une femelle d'axis qu'il tourmentait beaucoup pour la couvrir mais il était trop petit pour y réussir.").
× Odocoileus virginianus (♀) [White-tailed Deer] CHR. DRS. See: Axis axis × Dama dama. Lantz 1910 (p. 23).

Cervus duvaucelii [Swamp Deer | Barasingha]
See also: Axis axis.
× Cervus unicolor [Sambar] NHR?? CON: northern India. In a brief article, Mr. Frank Finn, Deputy Superintendent of the Indian Museum, opposes the opinion of Mr. David Ezra that an animal killed in the vicinity of Cooch Behar, India in the late 1800s was a probable hybrid of this type. Finn 1902.

Note: In Europe, Cervus elaphus is referred to by the common name “red deer,” whereas in North America the common names are “elk” or “wapiti.” These two deer have often been treated as separate species (Cervus canadensis in the New World and Cervus elaphus in the Old World), particularly since the publication of Pitra et al. (2004), but the two have often simply been lumped under the name Cervus elaphus. Hybrids of the two are fertile in both sexes (Flower 1929a, p. 317; Gray 1971, p. 152; Howard 1965; Lantz 1910; ; Rörig 1903; Seitz 1959a; von Knottnerus-Meyer 1904; Wodzicki 1950). Here, deer hybrids involving Cervus canadensis are listed under the name of Cervus elaphus.

Note: Captive deer hybrids are known between two types (nippon, taiouanus) formerly treated as separate species, but now as races of C. nippon.International Zoo Yearbook 1973 (p. 339)

Cervus nippon [Sika Deer]
See also: Axis axis, Cervus elaphus.
× Cervus unicolor [Sambar] CHR. CON: southern China? A few sambar/sika deer hybrids were produced at Woburn in the U.K. (Whitehead 1993 p. 312).
+ Ovis aries (♂) [Domestic Sheep] In Kunming, China, at the Yunnan Wild Animal Park, a ram and a sika doe formed a mated pair and have been many times photographed mating with each other. Neither of these animals was interested in sexual partners of its own kind. See also the separate article "Sheep-deer hybrids." Internet Citations: SMACK

Cervus unicolor [Sambar] (2n = 56)
See also: Axis axis; Cervus duvaucelii;C. elaphus; C. timorensis; C. unicolor.
× Bos indicus [Zebu] It's pure speculation, and no such hybrids have been formally reported, but the appearance of a strange animal photographed in northwestern India is suggestive of a sambar-zebu hybrid.
× Odocoileus virginianus [White-tailed Deer] CHR. DRS. In correspondence with Brown published in The American Naturalist, Caton says that he produced a sambar/white-tailed deer hybrid, but gives no details. Brown and Caton 1880 (p. 396).

Muntiacus muntjak [Indian Muntjac]
See also: Axis axis
× Muntiacus reevesi (↔) [Reeves’s Muntjac] CHR. HPF(♀♀)? CON: southeastern China. F₁ body size and antler pattern resemble M. reevesi, but coat color resembles M. muntjak. These muntjacs differ markedly in karyotype and chromosome counts (2n = 6/7 in M. muntjak and 46 in M. reevesi.). Early authors (e.g., Ackermann 1898, Przibram 1910) claim that female hybrids from this cross are sometimes fertile. Shi and Pathak (1981) found no mature spermatozoa in the testes of a three-year-old hybrid. Nietzel et al. (2012) examined a male hybrid (male Indian × female Chinese) and found that "A considerable number of spermatocytes degenerate, while others are able to enter meiosis II without completion of meiosis I and undergo a mitotic division leading to diploid speramtids." They did not, however, detect any mature spermatocytes. NKing 1993 (p. 150); Shi et al. 1980; Shi 1980; Shi and Pathak 1981; Zuckermann 1953 (p. 891).
× Muntiacus vaginalis [Northern Red Muntjac] NHR. ENHI. A parapatric contact zone extends across the Malaysian Peninsula, heading almost due south from Surat Thani to Khlong Thom in the south. Groves (2005) reported the presence of probable hybrids in this region. Parapatric distribution between similar organisms, in conjunction with initial reports of natural hybrids, usually implies the existence of a hybrid zone. So extensive hybridization can be inferred.

Muntiacus reevesi [Reeves’s Muntjac] See: Muntiacus muntjak.

Muntiacus vaginalis [Northern Red Muntjac] See: Muntiacus muntjak.

Odocoileus columbianus [Black-tailed Deer]
× Odocoileus hemionus (↔) [Mule Deer] CAENHR(Cascade Mountains, northwestern U.S.). HPF(♂&♀). Although once treated as separate species, these these two types of deer are now usually lumped. Latch et al. 2011 state that Black-tailed Deer and the Mule Deer "are morphologically, ecologically and genetically distinct, yet hybridize readily along a zone of secondary contact between the east and west slopes of the Cascade Mountains (Washington and Oregon, USA). Using microsatellite and mitochondrial DNA, we found clear evidence for extensive hybridization and introgression between lineages, with varying degrees of admixture across the zone of contact. The pattern of hybridization in this region closely resembles a hybrid swarm; based on data from 10 microsatellite loci, we detected hybrids that extend well beyond the F1 generation, did not detect linkage disequilibrium at the centre of the zone and found that genotypes were associated randomly within the zone of contact." See also: Cowan 1936; Jackson 1921†; Wallmo 1981.

Rangifer tarandus [Caribou | Reindeer] See the separate article “Reindeer × Cow.” Although both animals called caribou and ones called reindeer are referred to by the same scientific name, Rangifer tarandus, the caribou is a wild animal, while the reindeer, as its name suggests, is a semidomesticated animal. As might be expected, feral reindeer interbreed with wild caribou. Thus, with respect to deer hybrids of this type Mager et al. (2011; see Internet Citations: RANGI) state that, “Reindeer herding was once widespread on Alaska’s North Slope. Inupiat reindeer herders from Barrow, Alaska witnessed the loss of their reindeer to wild caribou in the 1940s and, though reindeer survival is presumed to be low in the wild, many hunters and herders have observed reindeer-like animals in caribou herds. Our study investigates the implications of historical contact between reindeer and caribou through DNA analysis and interviews with elder reindeer herders and hunters. Interviewees shared detailed memories of the conditions under which reindeer were lost to caribou herds, and described the morphological and behavioral characteristics used to distinguish between caribou and reindeer. They also expressed a range of perspectives on potential interbreeding between the two. Our genetic analysis reveals that though the North Slope herds demonstrate fidelity to calving grounds, gene flow is sufficient to counter genetic divergence between the herds. Within those herds, there are low but notable levels of reindeer introgression, with a few individuals putatively assigned as recent hybrids. Within domestic reindeer, one individual was identified as a caribou, and two others appear to be first-generation hybrids. Our results provide evidence of limited reindeer-caribou hybridization, but suggest that any historical reindeer-caribou interbreeding did not result in a large proportion of reindeer ancestry in North Slope herds.”